Project Summary/ Abstract Candidate: My long-term career goal is to be an independently funded scientist committed to the elimination of HIV/AIDS and substance use care and treatment disparities among Latino sexual minorities. The immediate and overarching goal of this proposal is to become equipped with innovative tools to examine the role of momentary-state substance use and psychosocial factors, and activity spaces, on antiretroviral therapy (ART) adherence among young Latino men who have sex with men (YLMSM) with HIV and gain foundational knowledge in the design of Just-In-Time Adaptive Interventions (JITAI). Career development plan: I require mentored training in 4 areas to reach my research and career objectives: 1) Latino sexual minority health and research issues; 2) clinical care and treatment of HIV and its syndemics; 3) Ecological Momentary Assessment (EMA) and Global Positioning System (GPS) technology; and 4) design of EMI and JITAI. The training and research plan will be guided by a team of experts: Drs. Trepka (HIV care and treatment; human subject research), Muoz-Laboy (sexual minority health), Devieux (intervention development), and Duncan (EMA; GPS). Environment: Florida International University (FIU) has a distinguished record of HIV and health disparity research and thus provides an intellectually rich environment for the proposed training and research. In addition to extensive physical resources, I will have access and exposure to expert researchers at the Center for Substance Use and HIV/AIDS Research on Latinos in the US and FIU?s Health Disparities Initiative (HDI). Research Project: The proposed study has two primary objectives. First, we will determine the role of momentary-state substance use and psychosocial factors and the activity spaces where ART occurs on ART adherence among YLMSM living with HIV. Second, we will assess the effect of frequent and repeated measures of ART adherence as a potential intervention for YLMSM and explore the acceptability of a related JITAI. To accomplish our objectives, we propose to implement an EMA/GPS study among 75 YLMSM ages 18-34 in Miami, Florida. The proposed innovative study will be the first to assess how daily changes in substance use, psychosocial factors, and activity spaces impact ART adherence. This information is critical to design JITAI that integrate daily patient-level risk data to adapt and deliver intervention components in real- time during patient?s everyday life. The study is significant because it targets a newly designated health disparity population for NIH research (MSM) living in a metropolitan area with the highest HIV diagnosis rate in the nation, thereby supporting the National HIV/AIDS Strategy objectives of reducing HIV disparities in populations at high risk, including Latinos, MSM, and persons living in the Southern US. In addition, the study will provide me with knowledge, expertise, and research findings to launch my independent research career and successfully submit an R-series grant to design, implement and examine the efficacy of a highly innovative and individualized JITAI that will use EMA/GPS technology to adapt to shifting barriers of ART adherence.